1. Field of the Invention
The invention relates to a system for applying labels to pallets movable along a conveyor line. More specifically, the invention relates to such a system which includes means for verifying the text on each label and for verifying that each label is correctly placed on the pallet.
2. Description of Prior Art
It is known in the art to provide a system for applying labels to packages which are moving along a conveyor belt. Thus, U.S. Pat. No. 4,321,103, Lindstrom et al, Mar. 23, 1982, teaches a system wherein a package is moved along a conveyor belt 10 to a weighing station which includes a computer unit 14. On the basis of the reading of the weighing unit, a label is printed in label printing and transport unit 20. The label is then moved into the nip between belts 38 and 40 to the label applying arm which includes, at the far end thereof, a roller 44. As seen in FIG. 3 of the U.S. Pat. No. '103, when the package 75 underlies the label applying arm, the roller 44 is moved downwardly to apply label 30 to the package 75.
Accordingly, it is known in the art to have a label dispenser in which a message on the label is printed on the basis of information from a computer unit. It is also known from the U.S. Pat. No. '103 to provide a means for transporting the label from the printing and dispensing unit 20 to the label applying station.
However, the U.S. Pat. No. '103 does not teach a system which verifies the message printed on the label, nor does the system as taught in the U.S. Pat. No. '103 verify that the label is properly placed on the package. In addition, the label applying system of the U.S. Pat. No. '103 is not suitable for applying labels on the front surface of a pallet movable along a conveyor line.
U.S. Pat. Nos. 3,783,058, Solomon et al, Jan. 1, 1974 and 3,954,542, Solomon et al, May 4, 1976, also teach label applying machines. Both of the Solomon et al patents also teach receiver units 351 for verifying the text and the positions of the labels. However, the system as taught in the Solomon et al patents is not at all suitable for applying labels to the front surface of a pallet movable along a conveyor line.
U.S. Pat. No. 3,960,640, Mort, Jr. et al, June 1, 1976, teaches a system for applying labels to the bottom of a product.
U.S. Pat. No. 3,970,831, Hegyi, July 20, 1976, teaches a digitizing system for programmably digitizing a control apparatus which provides control information to a machine to operate a tape placement head for the tape placement on a receiving surface. U.S. Pat. No. 4,248,655, Kerwin, Feb. 3, 1981, relates to an apparatus for controlling the positioning of indicia on a moving web. Neither of the above patents are useful for applying labels to the front end of a pallet movable along a conveyor belt.